Rotary sewing-machine.



R. K. HOHMANN. ROTARY SEWING MAGHINE. APPLIUATION FILED 00T. 1o, 190B.

Patented Feb. 141, 1911.

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R. K. VImHBaANN. Y ROTARY SEWING MACHINE. APPL-10ATION FILED 00T. 10, 19011.

v Patented Feb. 14, 1911.

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R. K. HOHMANN. ROTARY SEWING MACHINE.

APPLIOATION FILED 00T.10, 1908` Patented Feb. 14,1911.

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RICHARD K. HOHMANN, OF SAN DIEGO, CALIFORNIA, ASSIGNOR OF ONE-FOURTH TO EDWARD JEAN BERNHARD, OF LOS ANGELES, CALIFORNIA.

ROTARY SEWING-1VIACH`INE Application led October 10, 1908.

T o all whom t may concern:

Be it known that I, RICHARD K. HOH- MANN, a citizen of the United States, and resident of San Diego, in the county of San Diego and State of California, have invented certain new and useful Improvements in Rotary Sewiiig-lVlachines, of which the following is a specification.

This invention relates to sewing machines, and particularly to the type known as rotary machines, producing a lock stitch. Its objects are to provide a simple and efficient means for carrying the thread which constitutes the lower thread of the stitch and for looping the upper thread around the lower thread.

The main object had in view is the production of a practical and commercially successful machine which shall include a lower thread holder adapted to receive any ordiw nary spool of thread as well as any ordinary bobbin now used in rotary machines.

' I am aware that others have patented mechanisms intended to carry an ordinary spool as the bobbin for the lower thread in a rotary machine, but none of those machines is now manufactured commercially, and I believe this to be due to defects in principle and in design which have been overcome by my invention. It will be understood that in a rotary machine it is necessary in the formation of each stitch to loop the part of the upper thread carried down by the needle entirely around the lower thread carrier, and that where the lower thread carrier is made large enough to receive an ordinary spool of thread the difficulty in obtaining a smooth, easy and accurate operation is much greater than with the small holders for the ordinary bobbins. Furthermore, with the large specially constructed lower' spool carrier it is necessary to have a cooperating specially constructed take up, and my present invention includes such a take up. This take up is not specilically claimed herein, since it is made the subject of a separate application.

The novel features of my invention and the operation thereof will be understood from the following description taken in connection with the accompanying drawings.

.In the drawings: Figure 1 is a side view partly in section, showing aportion of a Specification of Letters Patent.

Patented Feb. 14:, 1911.

serial No'. 457,141.

work plate and head of a machine, together with my thread holders and looper below the work plate; Fig. 2 is an end view of the head with the end plate removed; Fig. 3 is a longitudinal section of the head showing a modified construction for operating the needle bar and take up; Fig. 11 is a perspective view of my holder for containing the lower thread; Fig. 5 is a plan view of the holder shown in Fig. et; Fig. 6 is an end view of the holder together with a portion of the work plate and an arm for preventing rotation of the holder; Fig. 7 is a longitudinal section of the holder in place in the rotary casing which loops the thread around it; Fig. 8 is an end view of .the rotary casing; Fig. 9 is a plan view of a modified form of thread holder; Fig. 10 is an end view of the holder shown in Fig. 9 mounted in a rotary casing and provided with an arm connected to the plate of the machine for preventing rotation of the holder; Fig. 11 is a side view of a rotary thread holder beneath the work plate of the machine together with means for rotating it; and Fig. 12 is an end view of the construction shown in Fig. 11.

In the drawings, 1 represents the work plate of the machine and 2 represents the head in which the needle bar 3 reciprocates vertically. This needle bar is operated from a rotary shaft 4 which carries upon its end a head made up of the two circular disks 5 and 6 rigidly connected together by wrist pin 7. The wrist pin 7 passes through an eye in the end of the link arm S which is pivotally connected at 9 to the upper end of the needle bar 3. On the outer face of the disk 6 there is a roller 10 working in the slot 11 in the take up arm 12, which take up arm is pivotally supported at 13 imme diately adjacent the edge of the disk 6. This take up arm is provided at its outer end with the usual eye 14 to receive the thread and the slot 15 to permit the easy insertion of the thread.

Tt will be observed that the rotation of the.

the elevation of the arm will be effected during about one fourth of the revolution of the disk G and that thus the motion of the arm in ascending is much quicker than when descending. This is because the roller 10 is working in the slot near the pivot when the arm is ascending and is farther removed from the pivot when the arm is descending, and it will be understood that the timing of the upwar'd motion of the take up may be adjusted and controlled by the position of the roller 10 on the face of the disk 6. rIhis quick take up with a long throw is specially designed for use with my thread carrying and looping means for the lower thread, since as hereafter explained my thread holder is made large enough to carry an ordinary spool of thread, and is consequently so large as to result in the formation of a long loop which passes around it.

It will be observed that in the form shown in Fig. 1 the needle bar does not pass through the top of the head Q but terminates therein below the disk 6.

In F ig. 8 I have shown a modified construction in which the needle bar passes through the head at 16 and it is connected to the front of the disk 6 by means of the link arm 8. In this instance the take up arm 19. passes between the disks 5 and 6 and the wrist pin 7 works in the slot 11, thus effecting the same motion as in the construction shown in Fig. 1. In this form however I prefer to bend the end 17 of the arm 12 so as to bring the eye 14 thereof to the front edge of the head. The plate 86 is secured in place by any suitable means and is removable so as to permit access to the parts.

The principal feature of my invention consists in the means for holding the lower thread and for looping the upper thread around it and forming a lock stitch. In the several figures of the drawings Ihave shown several different forms of thread holders, but they all have certain features of construction in common and the same fundamental principles of construction and operation underlie all of them.

In Fig. 4 I have shown a thread holder including a circular marginal rim 18 which is cut away from the point 19 to the pointwhere the hook 20 is formed. It will be observed that this cut-away portion extends over about one fourth of the circumference and that the loop engaging hook 20 faces this cut-away portion. A disk 21 is supported by the downwardly inclined spider arms 22 connected to the rim 18, and the radial arms Q3 connected to the rim 18 support at their ends the cylindrical casing Q-'l which is adapted to hold the thread. A shaft 9.5 extends outwardly from the disk 21 and is adapted to receive a spool 26 of ordinary thread of various sizes. On the end of this shaft there is a pivoted spring arm 27 which is adapted to be turned into the position shown in Fig. 4 so as to hold the spool 2G in place. It will be observed that while the shaft 25 is adapted to receive an ordinary spool it is also adapted to receive the bobbins which are ordinarily used in rotary sewing machines, and that therefore the operator may use either a spool or a bobbin in accordance with which happens to be the iost convenient at the time. The thread 28 from the spool 2G is passed through a slot in the cylinder 2stbeneath the tension plate 29 and upward through a slot cutin the end of that tension plate.

The form of thread holder shown in Fig. -l is intended to be stationary when the machine is in operation, and in Fig. 7 I have shown means for carrying the loop of the upper thread around this thread holder. This means consists of a case 30 secured to the end of the rotary shaft 81 and being of such a shape as to substantially conform to the shape of the rear side of the thread holder. This case 3() has an interior groove 32 furnishing a bearing for the rim 18 of the thread holder, and there is a screw threaded ring secured upon the outer edge of this case and having the inwardly turned flange S-l bearing upon the side of the rim 18 and securely holding it in place. By the use of this screw threaded ring the thread holder is securely held in place by parts which may be made very thin and light and at the same time very effective. In order to secure lightness, the case 30 is also made in skeleton form, embodying merely the outer rim connected by the curved cross piece 88. It will be miderstood that means may be used for locking the ring 33 to the case 32 so as to prevent it from becoming unscrewed during the rapid rotation of the parts. At one side the ring 33 has an overhanging segmental flange 85 inclined downwardly toward the axis and extending substantially to the end of the cylinder 211- so as to guide the thread over the end of that cylinder. It will be observed by reference to Fig. 8 that this overhanging flange extends only a comparatively short distance around the circumference,-and that its edges are made curved so as to permit the thread to slide easily over it. At the forward edge of this flange there is provided a loop engaging hook 86. It will be understood that the case 8O revolves around the spool holder and would naturally tend to make that holder rotate. In order to prevent this rotation I provide an arm 39 secured to the under surface of the table extending downwardly to a point adjacent the outer end of the cylinder 24 at 4G, and thence curving inwardly along that cylindcr to the point 4-1, where it rests upon the curved spring pressed member or arml2 carried by the end 1S) of the cut-away portion of the rim 18. This arm is curved as described in order to permit the flange 35 to pass freely by it, and by resting up'on the spring arm 4t2 it prevents the rotation of the thread holder'. From 'the point l1 the arm is continued in a curve around the back of the holder to a point near the margin of the disk 21 and this extension is for the purpose of guiding the thread up around the holder so that it will easily and freely pass between the arms -itl and 4t2. As shown the arms 22 extend inward from the rim at an angle of about 45o, making it easy for the loop to pass around the holder.

It will be seen by reference to Fig. G that the holder is retained in such position that the loop engaging hook 20 is adjacent, but to one side of the point, Where the needle passes down through the work plate. ln operation t-he rotation of the case 30 carries the point 36 through the loop of the upper thread formed by the needle, and since that hook faces in the opposite direction from the hook 2G it will carry the loop up to thahook which will then enter and engage the portion of the loop which is below the hook 36. rlhe continued motion of the case 30 will carry the ends of the loop around with it and by reason of the fact that this hook 36 is upon the forward inclined side of the case opposite to the side to which is attached the shaft 31 the thread will be made to pass around the end of the ease and will not be permitted to fall upon that side which is attached to the shaft 81. The flange or guard 35 will carry this thread outward so that it will properly pass over the end of the cylinder 24 and will not wrap around that cylinder or be caught thereby. The inner end of the loop which is engaged by the hook 20 is directed back down and behind the spool holder by the arms 22, thus passing behind the disk 21 and between it and the case 30. As seen in Fig. 7, sufficient space is allowed for the free passage of the thread between the holder and the case. llilhen the loop of thread has been carried to a point near the bottom of the thread holder the take up mechanism commences to operate so as to draw up that loop and as the loop is drawn up to a point near the end 19 it is being pulled by the take up so that there is practically no slack in it. lt passes beneath the guiding arm 113 and is drawn between the spring arm 42 and the bearing point L11 of the arm 39, these parts being so shaped that there is very little resistance to the passage of the thread. After the thread has pa d through this point the take up quickly draws it up around the lower thread, it being so adjusted that its quick upward stroke will occur at this time. By reason of the fact that my thread holder is of sufficient size to include an ordinary spool, and by reason of the fact that in the form shown in Fig. 7 it is necessary for the thread to ride up over the flange 35, there will be a 1ather long loop of the upper thread formed, and therefore it is necessary to have some such take up as that shown in Fig. 1 for quickly and prop erly (ilrawinpI the loop around the lower thread.

ln Figs. 9 and 1() the thread holder has the narrow bearing rim 18 as in Fig. il, and this rim is cut-away for about one fourth of its circumference for the same purpose as is indicated in connection with the form shown in l? ig. 4t. ln this instance however l do not use the cylindrical part 2st, but place arms iron the forward side of the rim inclined downwardly toward the axis, thus making the holder substantially symmetrical on both sides. It has the loop engaging hook facing the cut-away portion, and is provided with an arm i6 carrying a thread guide and adjustable tension. In this instance the spool is placed upon the shaft 47 and is held in place by the hinged arm 4:8. lt will be understood that in this form it is not necessary to use the flange on the casing 30, and that this casingl 30 terminates with the grooved portion indicated in Fig. 7 by the numeral 32, and that it is provided with a screw threaded ring corresponding to the ring 33, but without the depending flange ln this form of the device the arm 49 extends from the table top and bears upon the spring i2 so as to prevent rotation of the spool holder', and it is not necessary to give this arm t9 as much curvature as in Fig. G, since there is no flange 35 to interfere with it. The end of the arm Li9 is continued around behind the spool holder so as to serve as a guide for the thread in the same way as in the previously described form. ln operation it will be understood that the arms QQ and 4i direct the threads constituting the sides of the loop around opposite sides of the holder, and that the thread is drawn up by the take up in the same manner as provif ously described. lfilhile the form of holder shown in Figs. 4l to 7 has many ad Viantages over those previously in use, l prefer the form shown in Figs. 9 and 10.

In `Figs. 11 and 12 l have shown a spool holder which rotates instead of remaining stationary, 'and in this form l do not use a surrounding case for carrying the thread around the holder. rllhe thread holder in this instance is made up of a narrow mar ginal bearing rim as in the previous forms, and this rim is cut away for a portion of its circumference leaving a loop engaging hook 59 at one side. Arms 51, 52 extend downwardly and outwardly from this ring toward the axis and on the inner side these arms are secured to a disk against which the end of the spool fits. Un the outer sides the armsl are connected to a ring 5st providing a circular opening sufficiently large to permit the passage of an ordinary spool of thread. The spool of thread is placed upon a shaft 55 which has an outwardly curved head 56 loosely fitting within the ring 54e, the inner end of the shaft 55 being mounted to turn in the disk 53. The curved head 5G has a groove 57 across it in which its the arm 58 pivotally secured at 59 to the table top. This arm holds the shaft 55 containing the spool in place and prevents the spool from rotating with the spool holder, the lower end G() of this arm being inwardly curved as shown in Fig. 11. The head 56 is provided with a slot (51 through which the thread from the spool passes, and an adjustable tension device 02 is secured to the head at the end of this slot. The grooved ring 63 is secured to the table top by screws Gil and surrounds the spool holder and furnishes a bearing in which that holder rotates. A side plate 65 is secured to the end 63 by screws 6G and it serves to retain the holder in place within that ring. The ring G3 is cut away at G7 at the point where the needle passes through the work plate, and thus leaves room for the formation of the loop of the upper thread, which is to be engaged by the hook 50. The holder is provided with arms GS, 69 having therein the openings 70, 71 to be engaged by the devices hereafter described for turning the holder. The holder is turned by mechanism upon the end of the rotary shaft 72 mounted in bearings 73. lThis shaft has on its end a rocking arm 74 pivoted at 75 and carrying at its ends the pins 76, 7 7 adapted to enter the openings 70 and 7l. This pivoted arm 74 is rotated with the shaft 72 and is rocked upon its pivot so as to make the pins 7G and 77 alternately engage by means of a connection to the cam 78 which is secured to the arm 7 9 of the machine and which does not rotate. A sliding sleeve 80 is mounted upon an arm 81 carried by and parallel with the shaft 7 2, and this sleeve is given longitudinal motion on the arm 81 by a. roller S2 working in the slot 83 in the cam 78. This sleeve has a pin 84 working in the slot 85 in rock arm 7st, and thus that rock arm is turned upon its pivot as the shaft 72 rotates. The pins 7G and 77 are alternately withdrawn so as to permit the thread to pass around that 'side of the thread holder, it being understood that the thread passes one pin while the other is in engagement with the holder, and the parts are so timed that the thread will be properly drawn around the holder and will not be interfered with by these pins.

In the form shown in Fig. 11 it will be understood that the loop of the thread formed by the needle is engaged by the hook 50 and that the two sides of that loop pass down the inclined arms 5l, upon opposite sides of the holder. and therefore pass entirely around the holder, going under the retaining arm 5S.

lVhile in one form of the invention, as shown, the thread holder rotates, and in the other forms it is stationary, it will be observed that in all forms the holder is supported by a ring-like support either partially or completely surrounding it, and that there is relatife rotation between the holder and support. The width of the bearing surfaces may of course vary, but I prefer to make them narrow so as not only to make the parts light but to make it easy to direct the thread upon opposite sides of the holder. It will be further observed that the outer bearing ring or rim of the holder is cutaway throughout a portion of its circumference in front of the loop engaging hook so as to permit a free passage of the thread between the holder and support during the last part of each complete revolution. This free passage of the thread is found to be very advantageous in permitting the long loop surrounding the holder to be properly and successfully drawn by theY take up tight around the low-er thread forming the lock stitch. The length of the cut-away portion may vary in accordance with the kind of take up used, but I have found that when this portion extends about one-fourth the distance around the holder, the best results are produced.

Thile I have ref-erred to the bearing rim of the holder and to the bearing surface of the support as circular, I wish it to be understood that in using this term I do not wish it to be understood as necessarily limited to a complete circle, but as referring to the general shape rather than to the extent. It is intended to apply to forms in which a part or parts of the circumference are cut away.

lVhile my invention is primarily designed for use in carrying an ordinary commercial spool of thread, and my thread holder is shown large enough for that purpose, it will be obvious that some of its features of construction are applicable to thread holders made only large enough to contain a small bobbin and not a spool.

I have found that my form of take up embodying the slotted arm and roller is best adapted for taking up properly the long loop of thread formed in my device and that a cam of ordinary size for operating the take up arm cannot be made to successfully give the quick long upward stroke which is necessary. I have further found by experiment that the arm for preventing the rotation of the thread holder secures the best results when placed at the outer edge of the holder about level with its center. When so placed the thread will not bind when passing between the arm and holder and consequently be broken, but will pass through freely. If the arm is at the upper edge of the holder the thread will not only not be entirely released until it has passed that arm, but l :find that there will be a certain amount of binding as the thread passes the arm and frequent snapping of the thread will result.

Having thus described the invention, what is claimed is:

l. ln a sewing machine, the combination with a thread holder having a narrow circular bearing rim, of a thin ring-like support having on its inner side a groove extending inwardly from its edge in which said rim fits, and having upon its outer side a thin screw threaded ring engaging the threads of said support and having an inwardly turned flange for holding said rim in said groove.

2. In a sewing machine, the combination with a thread holder having a narrow circular bearing rim between its ends, a port-ion of the circumference of said rim being cut away, a loop engaging hook at the edge of and facing said cut-away portion, a ringlike support fitting said rim, means for securing relative rotation of the holder and support, a flange on said support for directing the thread around one side of said holder, and arms directing the thread around the opposite side of the holder.

3. ln a sewing machine, the combination with a spool holder, means moving in a single direction for passing a loop of thread freely around said holder, an arm secured to a fixed part of the machine and extending in the path of a portion of the holder to prevent rotation thereof, and a curved spring-pressed surface on said portion of the holder making contact with said arm and permitting the easy passage of the thread between said surface and arm.`

ll. In a sewing` machine, the combination with a thread holder having a circular bearing rim, a portion of which is cut away, a loop engaging hook at one edge facing said cut-away portion, a spring-pressed rounded bearing surface at the opposite edge of said cut-away portion, rotary means for passing a loop of thread engaged by said hook around opposite sides of said holder, an arm secured to the machine and makin g'contact with said spring-pressed bearing surface to prevent rotation of the holder.

5. ln a sewing machine, the combination with a thread holder, comprising a circular rim, a portion of which is cut away, of means for passing the sides of a loop of thread around opposite sides of said holder, an arm secured to a lixed part of the machine and extending within said cut-away portion below the top of the holder to prevent rotation of the holder, and a curved extension of said arm around the back of the holder to direct the thread between said arm and holder at the point of contact.

6. ln a rotary sewing machine, the combination with a thread holder having a circular rim extending more than one-half the distance around it, a circular rotary support for said rim moving in a single direction and so constructed as to pass a loop of thread freely around said holder between it and the support without making contact at any one point with both the holder and support, a fixed arm secured to the machine and bearing upon a portion of the holder to prevent rotation thereof, and means for permitting the thread to pass between said arm and holder.

7. In a rotary sewing` machine, the combination with a thread holder having a circular rim extending more than one-half the distance around it, a circular rotary support for said rim moving in a single direction and so constructed as to pass a loop of thread freely around said holder, between it and the support without making contact at any one point with both the holder and support, a fixed arm secured to the machine and bearing upon a portion of the holder to prevent rotation thereof, and a rounded spring-pressed bearing point between said arm and holder to permit the passage of the thread without binding.

S. In a rotary sewingV machine, the combination with a thread holder hai/ing a circular rim extending more than one-half the distance around it, a circular rotary support for said rim moving in a single direction and so constructed as to pass a loop of thread freely around said holder between it and the support without making contact at any one point with both the holder and support, a fixed arm secured to the machine and bearing upon a' portion of the holder to prevent rotation thereof, and a guide for directing the thread between said arm and holder at the point of contact.

9. ln a sewing machine, the combination with a thread holder having` a narrow circular bearing rim, of a ring-like support having on its inner side a groove extending inwardly from its edge in which said rim fits, and having upon its outer side a screw threaded ring engaging the threads of said support and having an inwardly turned flange for holding said rim in said groove, and a segmental downwardly inclined fiange to guide the thread around the holder.

10. A thread holder for rotary sewing machines, comprising a frame, a transverse marginal bearing rim a portion of the circumference being cut away, inclined arms on said frame extending inwardly from said rim on one side, a central cylindrical spool case on the opposite side connected to said rim, a central longitudinal spool carrying shaft within said fra-me andi spool case, means for holding a spool on said shaft, in combination with a rotary thread carrying support having a bearing groove engaging the end of said Spool case.

Said rim and a seniental flanfe on said enOaOinO Said rini and a semental ian'e 7 C C b b b 7 D O on said holder extending inwardly at an angle to direct the thread over the end of said Spool case. 15

In testimony whereof I aHiX my' signature in presence of two witnesses.

RICHARD K. I-IOHMANN.

IVitnesses I/V. WV. LAYWAN, ARTHUR L. BRYANT.

support adapted to direct the thread over 11. In a sewing` machine the combination with a spool holding frame having a g circular bearing rini partly cut away to receve a loop of thread, of a central longitudinal vspool carrying Shaft within said frame, a central cylindrical Spool case connected to said riin, a thread carrying rot-ary support having a circular bearing surface 

